Certain vehicles, particularly flat-bed carriers for transporting automobiles, are equipped with platforms or plates for carrying cargo, which are adjustable in height to facilitate loading and unloading operations.
These platforms are supported by an assembly of lifting frames that vary in number depending on the location and length of the platform. Each of these frames comprises two posts or dual lifting arms placed on either side of the vehicle, one on the right and one on the left.
Each of the posts or lifting arms is equipped with a hydraulic lifting device, conventionally one with a hydraulic auger motor or a hydraulic cylinder, for modifying the angle of the lifting arm or the height of the platform's recovery point and thereby varying the level of the platform supported.
To prevent undesirable torsion from damaging either the cargo being transported or the supporting platform itself, it is imperative that the movement of the hydraulic lifting devices be synchronized between both arms on a single lifting frame.
Synchronizing the positioning of the two left and right hydraulic devices on each lifting frame is necessary in order to keep the raised platform straight and horizontal and prevent it from slanting laterally.